A shorted-emitter thyristor is one which, for example, has electrode metallization ohmically contacting both a cathode emitter region and a cathode base region, wherein the cathode base region has a separate gate electrode connected thereto. This type of configuration decreases gate sensitivity because of the short, thus requiring greater gate current to drive the thyristor into conduction. This configuration does, however, have the advantage of minimizing unwanted temperature and dv/dt effects.
One known manner of increasing gate sensitivity, then, is to use a nonshorted-emitter configuration wherein the electrode metallization on the cathode emitter does not also contact the cathode base. This may not be acceptable, however, in applications where temperature and dv/dt considerations cannot be sacrificed.
A known manner of increasing gate sensitivity, with a shorted-emitter configuration, is to include auxiliary means in the gate circuit of the power thyristor. Such means may be either discrete from or integrated on a common substrate with the power thyristor. In the case of the latter, it is known to integrate an auxiliary or pilot thyristor on the same substrate with a power thyristor for controlling gate current thereto. The pilot thyristor fires first in response to gate current applied thereto, after which the power thyristor fires in response to gate current enabled by conduction of the pilot thyristor, the latter gate current being that current flowing through the pilot thyristor in its low resistance, high current "on" state.